使用Elasticsearch7.10.2新版本,新手需要注意的那些事

使用Elasticsearch,新手需要注意的那些事

全文搜索屬于最常見的需求，開源的 Elasticsearch （以下簡稱 Elastic）是目前全文搜索引擎的首選，簡稱es, 它可以快速地儲存、搜索和分析海量資料，維基百科、Stack Overflow、Github 都采用，

Elastic 的底層是開源庫 Lucene，但是，你沒法直接用 Lucene，必須自己寫代碼去呼叫它的介面，Elastic 是 Lucene 的封裝，提供了 REST API 的操作介面，開箱即用，

一 簡單和復雜搜索(Kibana)

1. GET demo/user/_search?q=name:張三 //使用Kibana測驗查詢
   

2. GET demo/user/_search
   {
     "query": {       //復雜查詢,排序,分頁,高亮
       "match": {
         "name": "張三"
       }
     }
   }      
   

3. GET demo/user/_search
   {
    "query": {
       "match": {
         "name": "張三"
       }
     },
     "_source": ["name","tag"] //結果過濾
   }
   

4. "sort": [
       {
         "age": {
           "order": "asc"
         }
       }        //排序
     ]
   

5.   "sort": [
       {
         "age": {
           "order": "asc"
         }
       }        
     ],
     "from": 0
     , "size": 20         //查詢條數
   }
   

6. GET kuangsheng/user/_search  //多條件查詢
   {
     "query": {
       "bool": {
         "must": [  //"shoud"//相當于or "must_not"相當于not
           {
             "match": {
               "name": "李四"
             }
           },
           {
           "match": {
               "age": "25"
             }
           }
         ]
       }   
     }
   }
   

7.  "filter": {    //過濾查詢
           "range":{
             "age":{
               "lt":23  //"gt"大于 "gte"大于等于 "lte"小于等于
             }
           }
         }
   

8. 精確查詢

• term 直接查詢(精確)

• match 使用分詞器(先分析檔案,然后在進行查詢)

  注意 text keyword型別不會被分詞器決議

9. 高亮查詢

GET kuangsheng/user/_search
{
  "query": {
    "match": {
      "name": "張三"
    }
  },
  "highlight": {     //自定義樣式 如:"pre_tags":"<p>" "post_tags":"</p>"
    "fields": {
      "name":{} //name型別高亮
    }
  }
}

elasticsearch回傳值

{
  "took" : 43,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 2.5226097,
    "hits" : [
      {
        "_index" : "kuangsheng",
        "_type" : "user",
        "_id" : "2",
        "_score" : 2.5226097,
        "_source" : {
          "name" : "張三",
          "age" : "25",
          "desc" : "gggg",
          "tag" : "渣男"
        },
        "highlight" : {
          "name" : [
            "<em>張</em><em>三</em>"
          ]
        }
      }
    ]
  }
}

二 SpringBoot集成Elasticsearch

1. 匯入

<dependency>
    <groupId>org.elasticsearch.client </groupId> 
    <artifactId >elasticsearch-rest-high-level-client</artifactId> 
    <version>7.12.0</version> 
</dependency>

官方檔案:https://www.elastic.co/guide/en/elasticsearch/client/

2. 配置連接客戶端的地址

@Configuration
public class ElasticSearchClintConfig {

    @Bean
    public RestHighLevelClient restHighLevelClient() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http")));
        return client;
    }
}

3. 測驗

	@Autowired
	@Qualifier("restHighLevelClient")
	private RestHighLevelClient client;
		
    @Test //測驗索引創建
	void testCreateIndex() throws IOException {
		CreateIndexRequest request = new CreateIndexRequest("kuang_index");
		CreateIndexResponse createIndexResponse = client.indices().create(request,           RequestOptions.DEFAULT);
		System.out.println(createIndexResponse);
	}

4. 添加檔案

    @Test
    void into() throws IOException {
        //創建物件
        User user = new User("張三", 33);
        //創建請求
        IndexRequest request = new IndexRequest("kuang_index");
        //設定規則
        request.id("1").timeout("1s");
        //將資料放入請求
        request.source(JSON.toJSONString(user), XContentType.JSON);
        //發送請求,獲取回應結果
        IndexResponse index = client.index(request, RequestOptions.DEFAULT);
        System.out.println(index.toString());
    }

5. elasticsearch jar包中對update,get,search,delete等都封裝了一系列方法

推薦狂神說的Elasticsearch教程:www.kuangstudy.com